Variable speed transmission



2 Sheets-Sheet 1 W. P. SCHMITTE R ET AL VARIABLE SPEED TRANSMISSIONFiled Jan. 23, 1937 Jqne 4, 1940.

INVENTQRS. Walter-P. Schmzfer Alfred 6.341412 ATTORNEY.

Patented June 4, 1940 UNITED s'rArss PATENT OFFICE VARIABLE SPEEDTRANSMISSION Walter P; Schmitter and Alfred G. Bade, Milwaukee, Wis.,assignors to The Falk Corporation Milwaukec, Wis, a corporation. ofWisconsin Application January 23, 1937, Serial No. 121,927

scams.

are driven through individual planet pinions" fixed thereto, from acommon sun gear, and power is transmitted therefrom through anencircling gear engaged with the pinions. Plane-- tary action of therollersis controlled bya traction ring which encircles and contacts therollers, contact pressures between the rollers and the control ringbeing maintained by urging the rollers bodily along their outwardlyinclined axes. This bodilyroller movement involves correspondingmovement of the attached planet pinions relative to the encircling gear.

An object of the present invention is to provide a on of the characterdescribed in which relative movement between the planet pinions and thedriven gear is reduced to a mini- Another object is to provide animproved transmission in which the sun' gear is eliminated and therollers driven by rotation of their supporting I carrier.

Another object is to further improve transmis sions of the characterdescribed.

Another object is to provide improved means for creating contactpressures between he rollers and the encircling ring.

Other objects and advantages will appear, either expressed or implied,from the following description of an illustrative embodiment of thepresent invention. I

In the accompanying drawings:

Figure 1 is a longitudinal sectional view of a variable speedtransmission embodying the present invention. a

Fig. 2 is a longitudinal sectional view of a second variable speedtransmission embodying this invention in another form. i

Fig. 3 is a view upon the line 3-3 of Figs. 1 and 2, showing the methodof mounting the ends of the rollers.

The variable speed transmission shown in Fig.-

1 of the drawings is somewhat similar to that described in theapplication identified above. It is enclosed in a housing 1i andincludes a driven shaft i2 iournalledin bearin s i3 and II in one end ofthe housing; A drive shaft l5, aligned with the drive shaft I2, isjournalled in a hearing it at the opposite end of the housing II and ina bearing I! mounted in a head I8 formed on the 7 end ofthe driven shaftI2.

Surrounding the drive shaft l within the housing II is a carrier l9.This carrier comprises a disk or head mounted on the drive shaft [5adjacent the bearing il in the head It;

and a second disk or head 2| likewise mounted on the drive shaft l5adjacent the hearing it in the housing ll. These two heads are rigidlyconnected by bars 22, preferably T-shaped in cross section. The .carrierI9 is secured to rotate with the drive shaft l5 .through appropriatemeans.

such as a key 23 in the head 2|.

Mounted in the carrier i9 is a set of preferably three taperedrelatively inclined planetary rollers 24, so arranged that their outeredges are normally substantially parallel to the common axis of theshafts l2 and i5, and so that their axes, if extended, would meet at acommon apex on the extended-axis of the shafts l2. and I5.

- Each of the rollers is journalled at its small end in a radially fixedspherical or self-aligning bearing 25, mounted in the head 20 of thecarrier. The opposite end of each roller is journalled in a radiallymoveable bearing 2 which is guided in a radial slot 21 in the head I Iof the other end of the carrier, so that each roller is free to swingoutwardly in an are about the fixed center of the spherical bearing 25;as a fulcrum, but at the samejtimeis firmly constrained to rotate withthe carrier l8. A

Each roller 24 carries a pinion 28 fixed thereto, several pinionsmeshing with and drivin an encircling ring gear 29, fixed to the head Itof the driven shaft II. In this instance, each pinion 28 is fixed to theiulcrumed end of its roller} adjacent the bearing 25 where its posi--tion, -l-relative to the gear 29, is least afl'ected by radial movementof its roller.

The planetary motion of the rollers 24 is controlled by a non-rotatingtraction ring 30 encircling and contacting the same and shiftablelengthvgise thereof to regulate their motion. Anv appropriate means,such for instance as that shown in the application above identified orin the'copending application of Walter P. Schmitter, Serial No. 121,119,filed January 18, 1937, may be employed for shifting and controlling theposition-of the ring 30 along the rollers.

It mill be noted that, since'the carrier if is directly driven by theshaft IS, the severalrollers 24 receive power from the shaft solelythrough .of rotation of the drive shaft l 5, and consequently that ofthe carrier, is ordinarily constant, these centrifugal forces remainsubstantially constant.

In both transmissions shown, provision is made for inducing andmaintaining pressure contacts r between the rollers 24 and ring 30, inaddition to those induced by centrifugal force. In both instances, thisis accomplished by the use of a rotary pressure ring 33 centrallydisposed within the group of rollers and axially moveable against thelarger free ends of the rollers to force them outwardly.

In the transmission shown in Fig. 1, the pressure ring 33 is supportedon an axially adjustable bearing 35 mounted on the drive shaft l5, thering 33 being urgedagainst the inclined surfaces of the rollers 24 by acompression spring 3| confined between it and an appropriate nut 32 inscrew threaded engagement with the shaft l5. A suitable thrust bearing34 is preferably interposed between the ring 33 and spring 3| to permitfree rotation of the ring without disturbing the spring 3|. With theparts thus arranged, the ring 33 maintains an outward pressure againsteach of the several rollers proportional to the pressure exerted by thespring 3|, which of course may be regulated and determined byappropriate adjustment of the nut 32.

The outward pressure thus exerted by the -pressure ring 33 against thefree end. of each roller 24 is sustained by the traction-ring 30 and bythe reaction of the bearing 25 acting as a fulcrum, and the resultingpressurefbetween each roller 24 and ring is dependent upon the tensionin the spring 3|, which is 'adjustably fixed, and also upon the axialposition of the traction ring 30 on the rollers. That is to say, whenthe ring 30 is disposed near the small ends of the rollers, andconsequently near the fulcrum bearing 25, the pressure between the ring30 and rollers, induced by the ring 33, is higher than when the ring 30is disposed near the larger ends of the rollers and remote from thefulcrum.

In the transmission shown'in Fig."'2, provision is made for renderingthe pressure inducing ring 33 responsive to the torque load on thetransmission, instead of to the adjustably" fixed pressure of aspring,so as to automatically increase the contact pressures between therollers 24 and traction ring 30 when the load increases and toautomatically reduce those pressures as the load decreases. In thisinstance the torque load on the traction ring 3!), induced by the actionof the rollers 24, is utilized to energize the ring 33. For this purposethe traction ring 30 is provided at its periphery with a bifurcatedprojection 36 adapted to loosely receive the thickened edge portion of aplate or fin 31 which projects radially from a rock shaft 38 journalledin thehousing and extending parallel to the axis of the carrier I9. Asegmental gear 39, fixed tothe rock shaft 38, engages the end of a lever40 which is toothed to mesh with gear 39. The lever 40 extends rad iallyfrom and constitutes an actuator for a cam disk 4| rotatable about anaxis-substantially coincident with the axis of the carrier I9.

The cam means shown in the present application is very simi ar to thatshown and described in the copendlng application of Walter P. Schmitter,identified above, Serial No. 121,119, filed January 18, 1937.

A plurality of balls 42, seated in radial cam grooves 43 formed in theface of disk 4| and in similar grooves 44 formed in the opposed face ofa stationary cam ring 45, function to force the disk 4| axially from thering 45 in response to movement'of the lever 4|. The several balls 42are positioned by an appropriate retainer ring or cage 46.

In this instance, the ring 45 is fixed in a cage 41 fixed at one end tothe end wall ll of the housing and projecting inwardly therefrom. A

hearing 48, seated in the inner end of the cage 41, provides supportforthe adjacent end of the carrier I9 through a supporting trunion 49journalled in the bearing 48. The disk 4| is provided with an extendedhub portion 50 which is'centered by the ring 45 and which is seated upona tubular member 5| loosely surrounding the shaft nailed on the tube 5|and a thrust bearing 54, between the head 52 and ring 33, insures freerelative rotation therebetween. A nut 55, threaded on the other end ofthe tube 5| and bearing against the cam disk 4|, may be adjusted toeliminate looseness in the connection between the cam 'disk 5| and ring33 and to establish an initial pressure between the ring 33- and rollers24.

The arrangement is such that any rotative impulse or torque load imposedupon the traction ring 30 by the rollers 24 is transmitted to the camdisk 4| through the fin 31, rock shaft 38, gear 39, and lever 40,tending to rotate the cam disk 4| relative to the cam ring 45 andthereby to urge the ring 33 more forcibly against the rollers 24 wherebythe contact pressures between the rollers and ring 30 are increased.Since the torque load on the ring 30 is proportional to the torque loadon the transmission, the contact pressures between the rollers and ring3|) are thus made to vary automatically in accordance with changes inthe torque load on the transmission, thereby assuring contact pressuresof suflicient magnitude to sustain the load when the load is heavy andto avoid unnecessarily high contact pressures when the load is light.

As hereinabove noted, a given pressure between the ring 33 and eachroller 24 produces a variable pressure between each roller 24 and thering 30 which increases automatically as the ring 30 approaches thesmall or fulcrumed end of the roller. Also the torque responsivemechanism just described functions to increase the pressures between therollers and ring 30. by automatically increasing the pressuresbetween'the ring 33 and rollers. In orderto avoid excessive pressures,provision is made for reducing the effect of the torque responsivemechanism uponthe ring 33 as the ring 3|) is shifted toward thefulcrumed ends of the rollers. This is accomplished 4n the transmissionshown by arranging the thickened edge of the fin 31 at an angle to therock shaft 38 so that as the ring 3|! is shifted toward the fulcrumedends of the rollers the efiective leverage of the fin, at the point ofcontact with the ring, is reduced.

It will be noted that in the transmission shown 'in Fig. 2, the carrierI9 is mounted wholly indeportion 58 which projects inwardly from the endhead. 20 of the carrier 7 Various changes may be made in either of theembodiments of the invention hereinabove specifically described withoutdeparting from or sacrificing the advantages of the invention as definedin the appended claims.

We claim:

1. In a variable speed transmission the com bination of a rotarycarrier, an axially moveable control ring, a plurality of taperedrelatively inclined planetary rollers rotatable with and with respect tosaid carrier and rockable radially of said carrier into pressure contactwith said ring,

said carrier having a radially fixed support for one end of each of saidrollers, and a pinion fixed to each roller adjacent said support. 7

2. In a variable speed transmission the combination of a rotary carrier,an axially moveable control ring, a plurality of tapered relatively inclined planetary rollers rotatable with and with respect'to said carrierand rockable radially of said carrier into pressure contact with saidring, a radially fixed bearing for onev end of each roller, a radialguide for the other end of each roller, and a pinion fixed to eachroller adjacent said bearing.

3. In a variable speed transmission the combination of a rotary carrier,an axially moveable control ring, a plurality of tapered relativelyinclined planetary rollers rotatable with and with respect to saidcarrier, each of said rollers being fulcrumed at one end in said carrierto rock radially into pressure contact with said ring and beingmaintained by said ring in an inclined position with the outer edge ofsaid roller substantially parallel to the axis of said carrier in all inall axial positions of said ring, and a pinion fixed to each rolleradjacent that part which is least affected by tilting thereof.

5. In a variable speed transmission the combination of a rotary carrier,an axially moveable control ring, a plurality of tapered'relativelyinclined planetary rollers rotatable with and with respect to saidcarrier and tiltable radially of said carrier, a pinion fixed to eachroller adjacent that part which is least affected by tilting thereof,and spring urged means for tilting said rollers into pressure contactwith said ring.

6. In a variable speed transmission the combination of a rotary carrier,an axially moveable control ring, a plurality of tapered relativelyinclined planetary rollers rotatable with and with respect to saidcarrier and tiitable radially of said carrier, a pinion fixed to eachroller adjacent that part which is least affected by tilting thereof,andtorque responsive means operable on said rollers to tilt the sameinto pressure contact with said ring.

7. In a variable speed transmission the combination of a rotary carrier,an axially moveable control ring, a plurality of tapered relativelyinclined planetary rollers rotatable with and with respect to saidcarrier and tiltable radially of said carrier into pressure contact withsaid ring, said rollers being maintained by said ring in an inclinedposition with the outer edge of said roller substantially parallel tothe axis of said carrier in all axial positions of said ring, a pinionfixed to each roller adjacent the point where it is least affected bytilting thereof, and a drive shaft connected to said carrierindependently of said pinions.

8. In a variable speed trasmission the combination of a rotary carrier,a drive shaft extending axially into said carrier, a plurality oftapered relatively inclined planetary rollers rotatable with and withrespect to said carrier, a control ring shiftable axially of saidcarrier to regulate the speed ratio of'the transmission, said rollersbeing radially moveable into pressure contact with said ring, a radiallyfixed bearing surrounding said drive shaft and radially spacedtherefrom, and a supporting hub on said carrier engaged with saidbearing to provide support for said carrier.

9. In a variable speed transmission the combination of a rotary carrier,an axially movable control ring, a plurality of tapered relativelyinclined planetary rollers rotatable with and with respect to saidcarrier and tiitable radiallyvof said carrier, a pinion fixed to eachroller adjacent that part which is least affected by tilting thereof,and spring urged means coacting with said carrier for tilting saidrollers into pressure contact with said ring.

WALTER P. SCI-IMI'II'ER. ALFRED G. BADE.

